Arrangement relating to ship hulls

ABSTRACT

A modification of a trimaran hull for improving the stability thereof in which the middle hull extends to a depth below that of the side hulls, the lower part of the middle hull having a rounded bow, and being considerably shorter in length than the side hulls and terminating forwards of the aft end of the side hulls.

United States Patent 11 1 Lauenborg 1 May 27, 1975 [54] ARRANGEMENT RELATING TO SHIP 2,371,478 3/1945 Steele 114/62 HULLS 2,757,629 8/1956 Wiltse 1 v v 1 114/125 2,815,730 12/1957 Horsdal 1 4 ll4/56 [76] Inventor: Jan Tronje Lauenborg, F elltun, 3,138,130 6/1964 Morgan 114/57 l640-Raade, Norway 3.177.836 4/1965 Salamin 114/61 3,239,856 3/1966 Stocking et aL 9/6 [22] July 1973 3.469557 9/1969 Wollard 9/6 2 Appll NO; 3 252 3.503.358 3/1970 Moesly ll4/l25 Primary Examiner-Trygve M. Blix [30] Fore'gn Apphcano Prmmy Data Assistant Examiner-Sherman D. Basinger Aug. 1, 1972 Norway 2744/72 7 [52] US. Cl. 114/665 R; 114/61; 114/665 S [5 1 AQSTRACT 51 Int. Cl B63b 1 12; 1363b 1/22 A mdlfiwmn of a hull for lmpmvmg the [58] Field of Search H 114/665 R 665 F 56, stability thereof in which the middle hull extends to 21 114/57, 6], 125; 9/6 depth below that of the side hulls, the lower part of the middle hull having a rounded bow, and being con- [56] References Cited siderably shorter in length than the side hulls and ter- UNITED STATES PATENTS minating forwards of the aft end of the side hulls 911 0 2,1909 4 Claims, 2 Drawing Figures Broward 1 14/665 R 1 ARRANGEMENT RELATING TO SHIP HULLS The invention relates to a special shape of ship hulls whereby it is intended to gain certain major adventages as compared to ship hulls of known shapes. The invention is particularly intended for forming of the hulls for smaller, fast vessels, such as motor torpedo boats, gunboats or the like, but can also be used advantageously for other types of vessels as, for example, relatively fast ferries and others.

Fast vessels, particularly the smaller types, will in heavy sea be subjected to high stresses and uncomfortable and detrimental motions. When moving against the sea, the vessels are not only subjected to very strong pitching motion and much water is washed over the deck, but also heavy pounding of the wave tops is applied against the bottom of the vessel. Sea from the side often gives a lurching motion or rolling which in extreme cases can endanger stability. Rolling chocks will detrimentally effect the manoeuvrability of the vessel.

In accordance with the invention, there is provided a ship hull of the trimaran type, where the middle part of the hull extends downwards to a depth below the side hulls and where the middle part terminates in a rounded bulb, the middle part having a substantially shorter lengthwise extension than the side hulls and being terminated a distance forward of the aft end of the ship hull.

In a preferred embodiment, the rounded bulb has the shape of a torpedolike body, the front end of which extends freely forwards of the connection to the main hull.

The bulb or the torpedolike body in accordance with the invention will therefore be situated at a greater depth than the rest of the bottom of the hull. When moving in sea, this body will generally always move through the water without being lifted out of the water even during very strong pitching motion of the vessel. This has the effect that waves will not be able to pound against the bottom of the hull as in previous hull designs and, at the same time, the buoyancy of the body will counteract digging of the bow into the sea. The motion of the vessel can be adjusted to the optimum by the arrangement of means in the body dividing it into trimming tanks and/or fuel tanks.

The connection between the bulb or the torpedolike body and the bottom of the hull extends only over a part of the length of the hull body. Thereby the turning diameter of the vessel will not be increased by much and the vessel will have good maneouvrability. The water resistance will be small since the body is torpedoshaped. Furthermore, the connection with the bottom of the hull is relatively narrow in section, so that the torpedo or drop shape of the surface of the body is interrupted only to an unessential extent.

ln sea from the side, the body and its part connecting it to the bottom of the hull, serve as a very effective rolling chock without reducing the maneouvrability to any extent.

Hydrophones and other equipment can be arranged inside the body if desirable. These will thereby have a much more advantageous position than previously in that they will be placed at a substantially greater depth.

By arranging the body in such a way that it comprises trimming tanks, not only will the possibility be gained for adjusting the trim for advantageous motion in sea but also for obtaining maximum speed.

The downwardly projecting body will also act as a wave dampener in sea pounding against the vessel from any direction, particularly when the hull of the vessel is lifted partly out of the water at high speed.

For a better understanding of the invention, reference is made to the drawings, wherein:

FIG. 1 shows schematically a vessel shaped in accordance with the invention as seen from the side, and

FIG. 2 shows the same vessel seen somewhat from behind in perspective view.

In the drawing, the torpedolike body is given the reference designation A and it protrudes downwards from the bottom near the bow section of the vessel.

The middle and aft section B of the vessel is shaped like a catamaran hull and, together with the protruding body A of the bow section C, a modified trimaran construction is obtained.

Any other shape of the bottom can be used with the arrangement according to the invention. Similarily, the invention covers any modification of the shape of the bow or torpedo-shaped body as long as this lies within the definition of being lengthwise extending, elongated and streamlined. It is furthermore possible to arrange more than one such body under the bottom of the vessel, for example, side by side and/or one after the other. Moreover, the body A can be divided into sections for use as trimming tanks and/or fuel tanks as shown in dotted lines in FIG. 1.

I claim:

1. A ships hull having a bow, stern, bottom and lateral sides and including two depending side portions which are spaced in opposition to one another and have free lower edges, said side portions defining at said bottom, a central longitudinal channel extending from the stern towards the bow, and a central portion disposed in said channel at the front thereof and including a downwardly projecting portion extending at a level beneath the free lower edges of said side portions and of substantially shorter length than the overall length of the hull, said downwardly projecting portion being disposed substantially in entirety below said free lower edges of the side portions and constituted as a horizontally extended torpedo-like body.

2. A ships hull as claimed in claim 1 wherein said torpedo-like body extends beneath the bow of the hull in spaced relation therefrom.

3. A ships hull as claimed in claim 1 wherein said torpedo-like body includes a front bulb portion which extends forwardly in spaced relation beneath the bow.

4. A ships hull as claimed in claim 1 comprising means dividing said torpedo-like body into a plurality of tank sections. 

1. A ship''s hull having a bow, stern, bottom and lateral sides and including two depending side portions which are spaced in opposition to one another and have free lower edges, said side portions defining at said bottom, a central longitudinal channel extending from the stern towards the bow, and a central portion disposed in said channel at the front thereof and including a downwardly projecting portion extending at a level beneath the free lower edges of said side portions and of substantially shorter length than the overall length of the hull, said downwardly projecting portion being disposed substantially in entirety below said free lower edges of the side portions and constituted as a horizontally extended torpedo-like body.
 2. A ship''s hull as claimed in claim 1 wherein said torpedo-like body extends beneath the bow of the hull in spaced relation therefrom.
 3. A ship''s hull as claimed in claim 1 wherein said torpedo-like body includes a front bulb portion which extends forwardly in spaced relation beneath the bow.
 4. A ship''s hull as claimed in claim 1 comprising means dividing said torpedo-like body into a plurality of tank sections. 